Re: [PATCH v3 3/5] thermal/drivers/generic-adc: Allow probe without TZ registration

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 13 Nov 2026 16:56:44 +0100
Luca Weiss <luca.weiss@fairphone.com> wrote:

> If the devicetree node is not referenced in a zone under /thermal-zones,
> devm_thermal_of_zone_register() will fail with -ENODEV.
> 
> Since the driver is now also registering as an IIO device[0], allow the
> probe to continue without the thermal zone.

Papering over problems, or expected path for some devices?  If it's
expected path we probably don't want to print a message with the
word failed in it.

> 
> We also can't use gadc_thermal_get_temp() anymore because we haven't
> necessarily initialized tz_dev.
> 
> Link: https://git.kernel.org/torvalds/c/3762f5851ac5 [0]
> Signed-off-by: Luca Weiss <luca.weiss@fairphone.com>
> ---
>  drivers/thermal/thermal-generic-adc.c | 20 +++++++++++---------
>  1 file changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/thermal/thermal-generic-adc.c b/drivers/thermal/thermal-generic-adc.c
> index c6a7a65aa6a6..40a34e97a515 100644
> --- a/drivers/thermal/thermal-generic-adc.c
> +++ b/drivers/thermal/thermal-generic-adc.c
> @@ -86,14 +86,16 @@ static int gadc_thermal_read_raw(struct iio_dev *indio_dev,
>  				 int *val, int *val2, long mask)
>  {
>  	struct gadc_thermal_info *gtinfo = iio_priv(indio_dev);
> +	int iio_val;
>  	int ret;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_PROCESSED:
> -		ret = gadc_thermal_get_temp(gtinfo->tz_dev, val);
> -		if (ret)
> +		ret = iio_read_channel_processed(gtinfo->channel, &iio_val);
> +		if (ret < 0)
>  			return ret;
>  
> +		*val = gadc_thermal_adc_to_temp(gtinfo, iio_val);

Maybe spin a helper that is used both in adc_thermal_get_get_temp()
and here?  Whilst it won't save much code (may actually be a touch longer)
it will put the two relevant steps in one place.


>  		return IIO_VAL_INT;
>  
>  	default:
> @@ -195,14 +197,14 @@ static int gadc_thermal_probe(struct platform_device *pdev)
>  						    &gadc_thermal_ops);
>  	if (IS_ERR(gti->tz_dev)) {
>  		ret = PTR_ERR(gti->tz_dev);
> -		if (ret != -EPROBE_DEFER)
> -			dev_err(dev,
> -				"Thermal zone sensor register failed: %d\n",
> -				ret);
> -		return ret;
> -	}
> +		if (ret != -ENODEV)
> +			return ret;
>  
> -	devm_thermal_add_hwmon_sysfs(dev, gti->tz_dev);
> +		dev_info(dev, "Thermal zone sensor register failed: %d\n",
> +			 ret);
> +	} else {
> +		devm_thermal_add_hwmon_sysfs(dev, gti->tz_dev);
> +	}
>  
>  	return gadc_iio_register(&pdev->dev, gti);
>  }
>